Viliam Geffert Carlo Mereghetti Beatrice Palano More Concise Representation of Regular Languages by Automata and Regular Expressions. 359-370 2008 Developments in Language Theory http://dx.doi.org/10.1007/978-3-540-85780-8_28 conf/dlt/2008 db/conf/dlt/dlt2008.html#GeffertMP08